Automotive vehicles may employ a fuel injected internal combustion engine in which a fuel injector discharges fuel into air in an intake manifold or combustion chamber of the engine and a spark plug ignites the fuel and air in the combustion chamber. The conventional fuel injector typically is controlled and responds to a fuel injection pulse width signal, which determines an amount of fuel injected. The fuel injection pulse width signal can be implemented to follow a programmed curve or algorithm, which is generally utilized to provide adequate engine performance when feedback or closed-loop engine control is not available. Similarly, the conventional spark plug typically is controlled and responds to an ignition timing signal that determines when the spark plug is activated. The ignition timing signal can be implemented to follow a programmed timing map, which is generally utilized to provide adequate engine performance when feedback or closed-loop engine control is not available.
Automotive vehicles may employ an oxygen sensor generally disposed upstream of an exhaust system and capable of sensing the oxygen level in the exhaust gas emitted from the engine. The oxygen sensor can provide a feedback signal used in controlling engine operation and adjusting fuel injection and ignition timing. However, at least some oxygen sensors need to warm up to a sufficiently high temperature before an accurate oxygen sensor reading may be obtained. Also, in the period immediately following an engine start, the oxygen sensor and other devices may not have acquired enough information to provide adequate feedback control. Therefore, for a period of time immediately following a cold start up of the vehicle engine, the oxygen sensor may not be capable of providing accurate information with which the engine may be controlled. As a consequence, undesirable hydrocarbon emissions may be emitted from the vehicle within the period immediately following start-up of the engine.
Additionally, immediately following a cold engine start, the catalyst of a catalytic converter can be ineffective since the catalyst may require a period of time to warm up to a temperature at which the catalyst can operate effectively. As a consequence, hydrocarbon emissions may be even higher during initial engine operation, especially after a cold start.